Yep, thats what I measured on the working channel, the negative side Q-7, Q-8 measures the same. The non working channel measures about the same on those devices. There is not any real difference till I measure the collectors of Q-9 and 10... those are a volt lower than the good board.

Yes, both boards measure within one or two tenths of a volt of each other on the MOSFETS. I had not mreasure across the resistors though and will do that in a little while. Am re-mounting the drovers after testing and am screwing heatsink and board together to make it easier to mount the drivers. Holding the heatsink, board, and hardware at same time is a bit difficult while keeping it aligned.

I will get back in an hour or so on the reading across those resistors.

If that doesn't work, get the scope out and try tracing the signal, see how far it gets.

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Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?

Actually the board drives my YAmaha NS-10 just fine so signal is flowing as normal... I had looked with a scope and it all seems fine. The problem is with that low voltage in both Q-9 and 10. It may be related to something behind it though... The OP stage doesn't even get warm!

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Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?

Hmm. Other than a soldering error, I can't think of anything else offhand. It's past midnight here, so I'll sleep on it and see what I can think of in the morning, assuming of course you haven't got it fixed by then.

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Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?